Oilfield operations typically involve the use of mechanical equipment, such as pumps and motors. This equipment is generally made of metallic substances and requires maintenance to continue to function properly. In the course of oil and gas drilling and production, this mechanical equipment may be present in downhole and subsea environments. These environments typically are corrosive environments. Such corrosive environments contribute to the corrosion of the mechanical equipment, including motors and pumps, which can cause them to fail.
Corrosion can cause problems in oilfield operations. Corrosion can increase drilling and production costs. Corrosion can also cause downtime in drilling, which leads to increased costs. To overcome these costs and delays, mechanical equipment having a hardened coating, such as a tungsten carbide coating, has been used to provide enhanced corrosion and wear resistance. However, due to the elevated costs of these coatings, only a small percentage of mechanical equipment in the field has this coating.
Corrosion inhibitors have been used to contain or prevent corrosion. Certain corrosion inhibitors include surfactants, which have been employed to inhibit corrosion or to improve the performance of certain organic corrosion inhibitor systems. Many oil wells produce mixtures having high water content, therefore, conventional oil-soluble mixtures have been formulated with both fatty acids and a variety of surfactants.
However, this approach has proven limited in its scope. The use of enough surfactant to render the oil-soluble molecule water-soluble has dramatically reduced film formation and film persistency, leaving the corrosion inhibitor susceptible to washing off of the metal, leaving the metal unprotected. Also, these inhibitors have a tendency to emulsify under downhole conditions, resulting in major problems for the user. Although these inhibitors have found limited use in oil and gas pipelines, they have not yet proven to successfully inhibit corrosion when utilized under the environments typical of producing oil wells.
In addition, corrosion in an oilfield environment may be initiated at a specific location on a specific piece of equipment at a specific time. However, such information on where and when corrosion may start may not be available to technicians in the oil field. This delay allows for the corrosion to progress, resulting in greater damage to mechanical equipment in the field.
In view of the above, it would be desirable to have an improved delivery system that supplies a sufficient amount of corrosion inhibitor at specific locations in order to stop or contain the corrosion in its early stages. It would also be desirable to supply a corrosion inhibitor that would be successful in containing or preventing corrosion under the environments typical of producing oil wells.